Blood plasma is a straw-colored liquid component of whole blood, in which blood cells, such as red blood cells and white blood cells, and other components of the whole blood are normally suspended. Whole blood is made up of about 55%, by volume, plasma. Plasma plays important roles in a body's circulatory system, including transporting blood cells, conducting heat and carrying waste products. Pure plasma contains clotting factors, which increase the rate at which blood clots, making it useful in surgery and in the treatment of hemophilia. Banked whole blood is sometimes used to replace blood lost by patients during surgery or as a result of traumatic injuries. However, if banked whole blood of a type compatible with a patient is not available, plasma may sometimes be used to replace some of the lost blood. Furthermore, plasma may be frozen and stored for relatively long periods of time until it is needed.
Plasma is collected from donors. Sometimes, whole blood is collected from a donor, and plasma is separated from the other components of the donated whole blood later, such as in a laboratory. However, in other cases, the plasma is separated from the other components of the whole blood at the donation site, and the other components are returned to the circulation system of the donor. Apheresis is a medical technology in which the blood of a donor or patient is passed through an apparatus, such as a centrifuge, that separates out one particular constituent and returns the remainder to the donor or patient. Plasmapheresis is a medical therapy that involves separating blood plasma from whole blood.
Donated whole blood is typically stored in plastic bags. However, collected donated plasma is typically stored in plastic bottles. A typical plasma bottle includes a closed neck with at least one nipple for connecting plastic tubing. Often, two nipples are provided, one for introducing plasma into the bottle, and the other for venting air out of the bottle. After plasma has been collected in the bottle, the tubing is cut off using heat-sealing tongs, leaving short (typically about 1½ inch long) sealed tubing stubs attached to the nipples.
These stubs typically project from the bottle neck and may pose problems during transport and storage. For example, when the plasma is frozen, the plastic of the stubs becomes brittle and may break, thereby violating the requirement to keep the plasma in an aseptic container. Prior art plasma bottles have been designed to attempt to overcome problems associated with the stubs.
For example, German Utility Model DE 200 10 825 U 1, the entire contents of which are hereby incorporated by reference, discloses a plasma bottle with a rotatable protective cap with at least one slot. Two sealed tube stubs project through respective slots, until the cap is rotated. Rotating the cap draws the stubs inside the cap, where they are physically protected from impact. The cap includes a resilient rib and tabs on the inside cylindrical surface of the cap. The rib and tabs project radially inward. The bottle neck includes fins that project radially outward. The fins and the rib and tabs cooperate to create a stop to inhibit rotation of the cap from one of two positions. However, this design does not fully solve the problems associated with plasma collection bottles. For example, the stop is easily overcome. Furthermore, the cap may be relatively easily dislodged from the bottle, such as when several bottles are packaged together in a container for shipment or storage.